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1,016
UPLOADS


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1,016
texts
Year
1
1958
1
1948
129
1934
124
1933
122
1932
143
1931
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9
Table of Contents
8
Index
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Creator
17
curtiss, l.f.
12
rossini, f.d.
10
coblentz, w.w.
9
snow, c.
7
isbell, h.s.
7
judd, d.b.
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1,016
English
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In the spring of 1916 an investigation of some of the forms of gas-detectors in use was begun by the Bureau of Standards. None of the existing forms of apparatus was found suitable for all purposes, and the investigation has led to the design of several new forms, which are more reliable than the old ones or better adapted to certain specific uses. All the new devices described depend upon the combustion of the gas contained in the surrounding atmosphere at the surface of an electrically heated...
At sufficiently high frequencies difficulty is encountered in discussing the resistance of a coil owing to (1) the skin effect and (2) the capacity effect. The capacity effect is dealt with in the present paper, and it is believed that the modifications introduced in this treatment by the skin effect are only minor. The capacity effect results in the non-uniform distribution of current in the coil considered. It appears to be necessary to define the resistance of a coil not for the coil as a...
The landing of aeroplanes can be facilitated by emitting from the landing field a vertical beam of radio-frequency electromagnetic radiation. A type of transmitting coil antenna has been devised for this purpose by J.A. Willoughby, of the Bureau of Standards. The behaviour of this transmitting coil antenna is calculated in the paper. Formulæ are worked out for the current received in a coil aerial and in an antenna oriented in a known manner at a sufficient distance from the transmitter. It is...
The paper describes chemical tests made on several standard brands of commerical ammonia. The results of these analyses indicate that most commercial ammonias contain less than 0.1% of impurities. Five methods of the preparation of pure samples of ammonia are described and a sample was prepared which contained, as far as any known test indicated, no organic impurities, less than 1 part in 1,000,000 by volume of non-condensing gases, and less than 0.003% by weight of water. The following...
The work described in this paper was undertaken for the purpose of satisfying an increasing demand for accurate data on the thermal expansion of molybdenum.
Topic: Table of Contents
Topic: Index
Topic: Index
Topic: Table of Contents
Striæ in optical glass may be divided into two classes; (i) those which appear as isolated bright streaks on a dark background, and (ii) those in which such bright streaks are very numerous and run into one another. This paper describes the investigation of a specimen of the former variety, containing a single approximately plane and very narrow stria - resembling a crack in the glass - which was ground and polished so that the stria was approximately perpendicular to the polished...
The pressure gage- a number of quartz plates suitably cut are arranged condenser fashion in a stack and introduced in an electric circuit. The quartz plates are subjected to the gas pressure to be measured by means of a piston. The combination of these constitutes a gage which is screwed into the wall of the gas chamber and the leads are brought out through holes drilled through the wall. The rec ording galvanometer- a ballistic galvanometer whose period is long compared to the duration of the...
Topic: Index
The object of the present paper is to give data on the reflecting power of the latest production of stellite and also of lacquered silver mirrors. It is shown that the reflectivity of stellite varies somewhat in the visible spectrum depending upon the homogeneity and no doubt upon the exact composition of the alloy [see Abs. 1918A01156]. Data are given on the reflecting power of lacquered silver mirrors, before and after exposure to ultra-violet light. It is shown that owing to photochemical...